Method of making shoe stiffeners



Nov. 16, 1937. B. E. SCHWARZ El AL 2,099,037

METHOD OF MAKING SHOE STIFFENERS Filed March 16, 1934 3 Sheets-Sheet l //\/l/E/V TURYE Nov. 16, 1937. B. E. SCHWARZ ET AL METHOD OF MAKING SHOE STIFFENERS 3 Sheets-Sheet 2 Filed March 16, 1934 Nov. .16, 1937. B. E. SCHWARZ ET AL METHOD OF MAKING SHOE STIFFENERS 3 Sheets-Sheet 3 III I Filed March 16, 1934 Patented Nov. 16, 1937 UNITED STATES FATE? ME METHOD OF MAKING SHOE STEFFENERS Application March 16, 1934, Serial No. 715,960 In Great Britain March 23, 1933 10 Claims.

5 which are impregnated with a solution of a cellulosic stiffening substance in a volatile solvent and, while still soft and pliable, are packed for shipment in sealed containers to be removed from the containers and, without further treatment, incorporated in the uppers of boots and shoes.

It is desirable, in the manufacture of such stiffeners, to pass porous absorbent blanks in succession through an apparatus which will impregnate them in such manner that they w ll contain just the proper amount of stiffening sub-- stance and solvent, and at the same time will be in proper condition to be packed for shipment in the sealed containers. The cellulosic stifiening substances which are particularly suitable for use in shoe stifieners are cellulose esters, such for example as pyroxylin, with or without the addition of plasticizers, the most economically available materials being celluloid scrap and discarded moving picture film. When, however, a cellulose 5 ester stiffening substance, for example celluloid,

is dissolved in avolatile solvent, such for example as acetone, the solution becomes very viscous when it contains 20% or thereabouts by weight of celluloid, and from this viscosity characteristic certain difficulties arise. The stiffeners must carry a suificient amount of the stiffening substance to render them properly strong after they have been incorporated in the uppers of shoes and the solvent has evaporated; and in order a to cause the stifieners to carry a sufficient amount,

it has been necessary to use an impregnating solution which contains more than 20% of the stiiiening substance. The viscosity of such a solution, however, is so high that the solution will 0 not readily permeate the blanks, and consequently a sticky coating of the Viscous solution remains on their surfaces and causes the blanks to tend to adhere to one another when they are brought into contact; Thus a solution of suificiently low 45 viscosity to permeate readily the stifiener blanks does not contain enough stiffening substance per unit volume, and a solution which does contain enough stiffening substance is so viscous that it will not readily permeate the blanks and has to- 0 be carried in part upon their surfaces.

According to the method of the present inventicn, porous absorbent blanks are impregnated by treating them with a solution of a cellulosic stifiening substance containing more than 20% v by weight of said substance to which has been added a viscosity reducing agent to increase the capability of the solution to permeate the blanks. By this procedure, in which the solution may contain 30% or more of the stifiening substance and 0 at the same time have a relatively low viscosity,

the impregnating solution may be caused to carry the required amount of stiffening substance into the interiors of the blanks, leaving on their exsurfaces very little if any sticky coating.

It is desirable that certain margins of shoe stifieners, after their incorporation in shoes, should be somewhat softer than their body portions. For example, the rear margin of a toe stiffener in a finished shoe should have such a quality. In order to produce this result the stiffener blanks, before they are impregnated, may be compressed along a selected margin whereby this compressed margin will take up less of the impregnating solution per unit volume than does the body portion of the stifiener. When such a stiffener has been incorporated in a shoe and the solvent has evaporated, the margin of the stiffener which was compressed will be more pliable than the remaining part of the stiffener.

In the illustrated apparatus, which is particularly designed for the manufacture of toe stiiieners, the blanks after having had their rear margins compressed are placed upon a conveyor which carries them to an impregnating apparatus where they are first immersed in a solution of stiffening substance, then progressively squeezed between rolls which carry coatings of the solution and are finally calendered and deposited in a receptacle ready to be packed in sealed containers.

Referring to the accompanying drawings, a complete apparatus by the use of which the method may be practiced is shown in Figs. 1 and 2 when these figures are placed side by side.

Fig. 1 is an elevation of the mechanism for compressing the rear margins of the stiffener blanks and conveying them to the impregnating apparatus,

Fig. 2 is an elevation of the mechanism for impregnating the blanks and for depositing them in a receptacle,

Fig. 3 is a plan on an enlarged scale of the small cables which form the conveyor ll, a plurality of blanks being shown in the positions which they occupy on the conveyor,

Fig. 4 is a development of the surface of one of the rolls of the impregnating apparatus, and

Fig. 5 is an elevation of another form of impregnating apparatus.

The illustrated apparatus is particularly designed for the treatment of toe stifiener blanks made of a porous absorbent material, such as cotton flannel, by impregnating them with a solution of a cellulosic stiiiening substance, such for example as pyroxylin or celluloid, and depositing the impregnated blanks while still soft and pliable in a receptacle from which they may be removed and packed for shipment in air-tight containers so as to maintain the stifieners in condition to be incorporated at any time in the uppers of shoes. The solution employed may, for example, contain 30% of celluloid by weight being given a suitably low viscosity by reason of the presence of a small percentage (for example,

a viscosity reducing agent, such for example as potassium acetate, which is incorporated in the solution. The ingredients of the solvent may comprise the usual ones, such for example as alcohol, benzol and acetone, along with suitable quantities of butyl-acetate and diacetone alcohol, these latter being used to guard against the efiects of moisture in different stages of the drying of the toe stiffener in the shoe. The dissolving of the celluloid in the solvent mixture is accomplished at a temperature of about 25 C.,

viscosity reducing agent is now allowed to per form its function by permitting the solution to stand for about twenty-four hours at a temperature of 35 to 40 C. at the end of which time the viscosity of the solution will have fallen to a point which will permit it readily to impregnate the blanks.

Although a single viscosity reducing agent has been mentioned above, it should be understood that there are other such agents, for example the acetates of sodium, cobalt and cadmium, and that any of the known viscosity reducing agents and procedures may be employed to obtain a solution or" a cellulosic stifiening substance having the desired high solid content and relatively low viscosity.

Suitable porous absorbent blanks having been died-out of a sheet, first have their rear margin compressed for the reasons explained above. This operation may be performed by a press having heated dies and of the character of the press which is commonly used for heating thermoplastic toe stifieners and pressing them into the uppers of shoes prior to the pulling-over operation, a press of this general type being indicated at 3 in Fig. 1. For the present purpose, however, the lower die ll of the press is locked against yielding movement, and the driving mechanism is such that on depressing a treadle (not shown) the upper die !3 descends to apply pressure to the margin of the blank interposed between the dies, remains in pressure-applying position for a determined time and then rises.

'No further description of the press will be given since the details of its construction form no part of the present invention and any suitable press maybe used. The pressing period of the illustrated press is about five seconds and the dies aremaintained at a temperature of about C., the rear margin of the blank preferably being moistened before the blank is presented to the press. In the region of the blank which has thus been pressed the fibre of the cloth is compressed which results in reducing the thickness of the blank in that region and providing a surface on the blank which is more resistant to impregnation than the part of the blank which is still in its soft and very porous condition. Consequently when later this blank is treated with the impregnating solution, the compressed rear margin will absorb less of the stiffening substance than the remainder of the blank.

Two such'presses side by side (only one of which is shown) are provided since one operator can readily attend to two presses. The conveyor ll consists of a plurality of small cables, as best -,shown in Fig. 3, on which the stifiener blanks I00 1% by weight of the weight of the celluloid) of are placed one at a time by the operator of the press so as to occupy the staggered relation shown in Fig. 3. The small cables which form the conveyor I1 pass around an adjustable grooved pulley l9, then upwardly into a cover 22 (Fig. 2), which encloses the impregnating apparatus, over a grooved pulley 2 I, then down around a grooved delivery pulley 23, then up over a grooved pulley 25, then out of the cover 22 and down under a grooved pulley 21 (Fig. 1) and thence to the pulley l9, said conveyor being driven from the impregnating apparatus, as will appear later. The operator of the press 3 operates the press to compress the rear margins of the stiffener blanks and places the blanks at regular intervals one near one edge of the conveyor l1 and the next one near the opposite edge of the conveyor so that, as the conveyor moves along, the blanks occupy the positions shown in Fig. 3.

The roll 23 (Fig. 2) delivers the pressed blanks one by one at regular intervals to a conveyor 29, also made of small spaced cables, which carries the blanks to the impregnating roll 3|. The blanks are transferred from the impregnating roll 3| to a roll 33, which acts both as an impregnating roll and as a calender roll. They then pass between the roll 33 and an upper calender roll 35, then between'the roll 35 and a small calender roll 31, and finally to a pulley 38 which delivers them into a receptacle 39. From this receptacle the stifieners are removed and packed in sealed containers so as to maintain them in their soft and pliable condition ready at any time to be taken out and incorporated in the uppers of shoes. The various rolls and pulleys are rotatably mounted in a frame which is supported on a hollow base 4| upon which is also supported a tank 43 for the impregnating solution, said solution being maintained at the level shown so that the lower portions of the rolls 3|, 33 are immersed in it. The small cables of the conveyor 29, after they leave the roll 23, run on the periphery of the impregnating roll 31 until they approach the bite of the rolls 23, 33; they then run in grooves of a depth approximately equal to their diameters in the roll 33 until they approach the bite of the rolls 33, 35; they then run on the periphery of the roll 35 until they approach the bite of the rolls 35, 31; they then run in grooves in the small calender roll 31. From this roll they run around the grooved'pulley 38, over a grooved pulley 45 and over a small grooved roll 41 mounted at the outer end of a pivoted arm 43 which may be swung about its pivot by means of a screw 5| to apply tension to the conveyor 29. The conveyor then passes part way around the roll 33 in the grooves in that roll, then around a grooved pulley 53 and then up and around the grooved roll 23. Another conveyor 55, also composed of small cables, passes in grooves around the impregnating roll 3!, then up over the periphery of the roll 33, then in grooves in the roll 35, then up around a small grooved pulley 51', then down into the grooves in the roll 35, then past a small grooved roll 59 which serves to tension the conveyor 55 in the manner in which the small roll 4'! tensions the conveyor 29, and thence to the grooves in the pulley 3i. It will be understood that in those localities in which the conveyors 29 and 55 are adjacent to each other, the cables of one conveyor run between those of the other.

Considering now a blank which has been delivered by the roll 23 to the cables of the conveyor 29, this blank will first be pressed against the periphery of the roll 3| which carries a coating of the impregnating solution; it will then be immersed in the solution. As it approaches the bite of the rolls 3|, 33, the cables of the conveyor 29 leave the periphery of the roll 3| and enter grooves in the roll 33 so that the blank is free to leave the roll 3|. It is compelled to leave the roll 3| by the action of the cables of the conveyor 55 which leave the grooves in the roll 3| and pass over the periphery of the roll 33. The blank is thus transferred from the roll 3| to the roll 33, and the opposite face of the blank from that which was pressed against the roll 3| by the cables of the conveyor 29 is pressed against the roll 33 by the cables of the conveyor 55. During this transfer of the blank from the roll 3| to the roll 33, the blank is subjected progressively to a squeezing action between the rolls 3| and 33 since, at the bite of these two rolls, no cables are located between their peripheries. The opening between these rolls is small so as to sub ject the blank to a considerable squeezing action, said opening being adjustable by reason of adjustable eccentric bearings (not shown) in which the shaft of the roll 33 runs. The purpose of this squeezing action is to ensure thorough impregnation of the blank. As it passes from the roll 3| to the roll 33, the blank reacts from the squeeze it has just received and absorbs more of the impregnating solution which has been carried up from the tank by the roll 33. In other words, the blank acts in the manner of a sponge and the result of its expansion, after it has been squeezed or compressed, is to cause the impregnating solution to penetrate farther into the fibres of the fabric than it did during the immersion of the blank. As the blank approaches the bite of the rolls 33, 35, the cables of the conveyor 55 enter the grooves in the roll 35, and the cables of the conveyor 29 leave the grooves in the roll 33 so that the blank is transferred from the roll 33 to the roll 35 and is again progressively squeezed between the bite of these two rolls. The blank then passes between the bite of the rolls 35, 31 at which locality the cables of the conveyor 55 are in grooves in the roll 35 and the cables of the conveyor 29 are in grooves in the roll 31. At this point it is calendered to the desired thickness and all surplus solution removed.

; In order to permit the distance between the rolls 35 and 31 to be varied so as to provide for blanks of different thicknesses, the roll 3? is mounted for adjustment toward and from the roll 35. To this end the roll 31 is carried by an arm 38 which is held in adjusted position by a bolt 40 which passes through a slot in a portion of the frame of the apparatus. The finished stiifener, after leaving the roll 31, is carried over the pulley 38 and deposited in the receptacle 39, a stripper 6| being provided for removing the stiffener from the pulley 38. This receptacle rests upon a vertically movable support 63 under which are two rotatable eccentrics, one of which isshown at 65, which may be rotated by a handlever 51 to raise and lower the receptacle. The upper edge of the receptacle, when in the raised position shown, is forced against a heavy felt washer 69 carried by a receptacle holder II. This hermetically seals the impregnating apparatus at that end. The cover 22 completely encloses the upper portion of the impregnating apparatus, the only openings being those which permit the conveyor ll of the compressing apparatus to enter and leave the cover.

When the blanks are delivered from the roll 23 to the impregnating roll 3|, it is desirable that the localities of the roll 3| on which the blanks are received should carry a full coating of impregnating solution. Referring to Fig. 3, it will be seen that there are two rows of blanks on the conveyor I? which have been marked respectively A and B. The size of the blank-delivery roll 23 is such that it will deliver two blanks at each revolution, one blank from the row A and one blank from the row 13. The impregnating roll 3| has a cylindrical surface which is capable of accommodating six of the largest blanks operated upon, although it should be noted that it never does so during the operation of the apparatus. Fig. 4 shows a development of the cylindrical surface of the impregnating roll divided into six equal spaces marked respectively I to 6. The gearing between the delivery roll 23 and the im pregnating roll 3| is such that the delivery roll makes three revolutions to every two revolutions of the impregnating roll. Consequently the impregnating roll receives three blanks during each revolution of said roll. Bearing in mind that the blanks I90 are delivered alternately from the rows A and B, in the first revolution of the impregnating roll 3|, blanks will be delivered to spaces numbered 3 and 5. In its second revolution, blanks will be delivered to spaces numbered 2, 4 and 6. In its third revolution, blanks will be delivered again to spaces numbered 3 and 5. With such a construction, after a blank has been delivered to any given space, the roll will make two revolutions before another blank is delivered to the same space, said roll having made one revolution with no blank covering said space so that the surface of the roll represented by said space carries a fresh coating of the impregnating solution when a blank is delivered upon it. Every time therefore that a blank is delivered to the impregnating roll, said blank contacts with a surface of the roll which is thoroughly coated with impregnating solution.

It is desirable that the cables of the conveyor H which delivers blanks to the impregnating apparatus should not carry back to the press 9 (Fig. 1) any of the impregnating solution. To this end the grooves in the roll 23 (Fig. 2) which carry the cables of the conveyor 29 are much deeper than the grooves which carry the cables of the conveyor I1; and there are provided two small stripper rolls 73 having grooves which are of a depth less than the diameter of the cables of the conveyor 29 and two felt pressers 15. The stripper rolls are rotated by the friction of the cables in their grooves and remove most of the impregnating solution which is carried up by the cables of the conveyor 29. The two felt pressers are pressed firmly against the cables and remove the last traces of the impregnating solution. The calender roll 35 is mounted in bearings which may be adjusted vertically by turning knobs, one of which is shown at 77, so as to vary the space between the rolls 35 and 33. The roll 51 is adjustable vertically by turning screws, one of which is shown at 79; and the pulley 38 is adjustable upward to the right and downward to the left by turning screws, one of which is shown at 8|. In order to maintain the impregnating solution warm, for example at a temperature of 40 0., there is provided in the hollow base 4| a receptacle 83 for water in which is immersed an electric heating unit 35.

Any suitable mechanism may be employed for driving the various pulleys and rolls to cause them torotate in the directions indicated by the arrows. This mechanism has not been shown since its details of construction form no part of the present invention, and any suitable driving mechanism may be employed. The rolls and pulleys may, for example, be driven through gears, pinions, sprockets, sprocket chains in the following manner. The impregnating roll 3| is rotated slowly, at the rate of two or three R. P. lVL, from the driving shaft of the machine by means of a pinion on said shaft which meshes with a gear on the shaft of the impregnating roll 3i; and the other driven members are driven from this roll shaft. A gear on the shaft of the impregnating roll 3| meshes with a gear of equal size on the shaft of the roll 33, the upper calender roll 35 being driven by a gear on the shaft of that roll which meshes with a gear of equal size on the shaft of the roll 35. The pulleys 38, are driven by a sprocket chain which passes around a sprocket on the shaft of the pulley 38, under a sprocket on the shaft of the pulley over a sprocket on the shaft of the roll ti and around a sprocket on the shaft of the roll 33. The rolls 23 and 53 are driven respectively by series of pinions, the end pinion of each series meshing with a gear on the shaft of the roll 3i. The puleys 2|, 25 are driven from the shaft of the roll 53 by a sprocket chain which passes around a sprocket on the shaft of the roll 53, over a sprocket on the shaft of the pulley 25 and around a sprocket on the shaft of the pulley 2 I.

The mode of operation of the apparatus will be briefly described. The operator stands in front of the two presses, one of which is indicated at 9 in Fig. 1, presents blanks to the two presses in succession and causes them to oper ate to compress the rear margins of the blanks. These blanks are place on the moving conveyor I! and occupy the relative positions shown in Fig. 3. When they reach the roll 23 (Fig. 2) they are delivered to the cables of the conveyor 29 which first presses one of their faces against the periphery of the impregnating roll 3i. As the blanks continue their travel they are carried up out of the solution and transferred to the roll 33, having received a squeeze as they passed between the bite of the rolls 3 I 33. They are held on the roll 33 by the cables of the conveyor 55 until they approach the bite of the rolls 33, 35 where they receive a second squeeze and are transferred to the roll 35, being held on it by the cables of the conveyor 29. They are calendered to the desired thickness between the rolls 35, 31 and are then carried by the conveyor 29 to the strippers Etl where they are caused to fall into the receptacle 39.

In Fig. 5 there is shown another form of impregnating apparatus which be used in place of that shown in Fig. 2. The conveyor II delivers the blanks with their rear margins compressed to the roll it! (which corresponds to the roll 23 of Fig. 2) from which they are removed by strippers m3 and slide down over the strippers into position between the presser roll I95 and an impregnating roll N37. The impregnating roll IEll is the first one of three large rolls: of the apparatus and serves to carry the blank through the impregnating bath. The lower portion of this roll is submerged in the solution and carries along with itan amount of softening compound which is regulated at will by an adjustable stripper I09 at the top of the roll. In order to press the blanks firmly against the impregnating roll W'I, the presser'roll I05 must be set up close enough to press the blanks upon the coated roll Illl. Ithas been found that the blank will adhere to the smoother one of two surfaces. Since the roll IBI is provided with grooves into which extend feed fingers III, hereinafter referred to, provision should be made to keep the blanks from wrapping around the presser roll H95. To this end, deep grooves are cut in the presser roll, said roll being adjustable by means of adjustable block bearings so as to press the blanks firmly against the roll IIll. To ensure that the blank shall always encounter the same condition in the ap paratus at all times, it is necessary to provide not only the impregnating roll it? but also the lower and the upper calender rolls H5 and ill respectively with easily adjustable strippers which scrape off the surplus solution from these rolls and cause this surplus to return to the tank IIQ which holds the solution. The stripper I09 of the roll I 01 and the stripper I2I of the upper calender roll II? are made in the form of troughs which come to a point at the centers of the peripheries of the rolls and slope downwards at both sides. The lower calender roll 9 l5 has a stripper I23 situated at its lower portion just above the level ofthe solution in the tank.

As the blank travels at a slow speed, there is no danger that it'will leave the impregnating roll as it meets the solution. The blank which has already absorbed a quantity of solution when first brought into contact with the roll IE will now, in passing slowly through the solution, become further impregnated. As it is desirable to make the impregnation as thorough as possible so as to have every fibre of the fabric Well covered with the solution, the blank is now subjected to a squeezing operation between the roll ill! and the roll M5, the distance between these rolls at the point at which the squeezing is accomplished being for example about .065 of an inch in making toe stifieners for mens shoes. This distance may be varied by means of adjustable eccentric bearings in which the shaft of the roll H5 runs. After the blank has been thus progressively squeezed, it is taken off from the roll ill? by the fingers HI and guided, by reason of the shape of these fingers, upon the upper portion of the roll H5 to which the Wet blank clings. As it reacts from the squeeze it has just received, it absorbs impregnating solution which has been carried up from the tank by the roll H5. The blank then passes to the opening of predetermined dimension between the upper and lower calender, rolls ill and I I5 and is calendered to the desired thickness, any surplus solution that it may contain being squeezed out. Adjustment of the opening between these two last-named rolls is possible by means of adjusting knobs, one of which is shown at In order to avoid a possible bending over of the blank when it passes from the impregnating roll N31 to the lower calendering roll i l5, it is desirable to provide the latter roll'with a rough surface to which the wet, limp blank will firmly adhere as soon as it comes into contact with said surface. To this end the roll H5 may be provided with strips of steel having surfaces like that of a grater, said stripsbeing located between the grooves with which this roll is provided to accommodate the automatic blank-removing device hereinafter referred to. The roll H5 travels a little faster than the roll I07 in order to produce a pulling action on the blank as soon as the projections on the steel strips take hold of it, thus ensuring that the blank will be pulled out smoothly on the roll before reaching the point where it is to be calendered.

When the impregnating blank has been calendered it is compelled to follow the lower roll i I5, first because it clings to the steel strips, and sec-- end because there are associated with the upper calender roll Ill and extending into grooves in its periphery thin brass fingers I21 which prevent the blank from traveling upward on this roll, but instead take it off and direct it back upon the lower roll H5. To take the blanks ofi from the roll H there is provided a series of finetoothed wheels I29 projecting somewhat into the grooves of the roll I I 5, the wheels rotating in the same direction as the roll. At a little distance is another series of wheels I35 of larger diameter and also provided with fine teeth. These two series of wheels are connected by endless fine wire springs l 33 which form a conveyer for the blanks. After the blank has been taken oif from the lower calender roll i !5 by the teeth of the small wheels E29 and deposited upon the wire spring conveyer 533, it is carried by the latter to the larger fine-toothed wheels it! where the blank, in making the turn around these larger wheels, will fall off into the receptacle (not shown) placed at this point. The wire spring conveyer presents only a small surface to the blanks which it carries, and remains taut at all times since the springs are under some tension.

The driving mechanism for the rolls and wheels of this machine has not been shown since the details of its construction form no part of the present invention, and any suitable driving mechanism may be employed. All of the rolls and Wheels including the roll H5 will preferably be driven from the shaft of the roll iS'i, said shaft rotating slowly as has been stated.

Having described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. The method of preparing shoe stiifeners which comprises impregnating porous, absorbent blanks with a solution of a cellulosic stiifening substance containing more than 20% by weight of the substance and having a viscosity sufliciently low to permit it readily to permeate the blanks, and packing the stifieners while soft and pliable in sealed containers ready to be removed and placed without further treatment in the uppers of boots and shoes.

2. The method of preparing shoe stiifeners which comprises impregnating porous, absorbent blanks with a solution of a cellulosic stiffening substance containing more than 20% by weight of the substance to which has been added a viscosity reducing agent to increase the capability of the solution to permeate the blanks, and packing the impregnated blanks while soft and pliable in sealed containers ready to be removed and placed without further treatment in the uppers of shoes.

3. The method of preparing shoe stiffeners which comprises treating porous, absorbent blanks with a solution of a cellulosic stiifening substance containing more than 20% by weight of the substance to which has been added a viscosity reducing agent to increase the capability of the solution to permeate the blanks, removing the surplus solution, and packing the blanks while soft and pliable in sealed containers ready to be removed and placed without further treatment in the uppers of shoes.

4. The method of preparing shoe stiffeners which comprises treating porous, absorbent blanks with a solution of a cellulosic stiffening substance containing more than 20% by weight of the substance to which has been added a viscosity reducing agent to increase the capability of the solution to permeate the blanks, compressing and releasing the blanks during their treatment to ensure thorough impregnation, and packing the blanks while soft and pliable in sealed containers ready to be removed and placed Without further treatment in the uppers of shoes.

5. The method of preparing shoe stifieners which comprises treating porous, absorbent blanks with a solution of a cellulosic stifiening substance containing more than 20% by weight of the substance to which has been added a viscosity reducing agent to increase the capability of the solution to permeate the blanks, compressing and releasing the blanks during their treatment to ensure thorough impregnation, removing the surplus solution, and packing the blanks while soft and pliable in sealed containers ready to be removed and placed without further treatment in the uppers of shoes.

6. The method of preparing shoe stifieners which comprises treating porous, absorbent blanks with a solution of a cellulosic stiffening substance containing more than 20% by weight of the substance to which has been added a viscosity reducing agent to increase the capability of the solution to permeate the blanks, compressing and releasing the blanks during their treatment to ensure thorough impregnation, calendering the blanks, and packing the blanks while soft and pliable in sealed containers ready to be removed and placed without further treatment in the uppers of shoes.

7. The method of preparing shoe stifieners which comprises treating selected margins of porous, absorbent blanks to decrease the permeability of said margins, and treating the blanks with a solution of a stiifening substance to which has been added a viscosity reducing agent.

8. The method of preparing shoe stiffeners which comprises compressing selected margins of porous, absorbent blanks to decrease the permeability of said margins, and treating the blanks with a solution of cellulosic stiffening substance to which has been added a viscosity reducing agent.

9. The method of preparing shoe stiifeners which comprises impregnating porous, absorbent blanks with a solution of a cellulosic stiffening substance containing more than 20% and less than 40% by weight of the substance and having a viscosity sufiiciently low to permit it readily to permeate the blanks, and packing the stiffeners while soft and pliable in sealed containers ready to be removed and placed without further treatment in the uppers of boots and shoes.

10. The method of preparing shoe stiffeners which comprises decreasing the permeability of selected portions of porous absorbent blanks, treating the blanks with a solution of a stiffening substance, and compressing and releasing the blanks during the treatment.

BRUNO ERNST SCHWARZ. FLOYD DUDLEY DEAN. 

